Research on Agricultural Carbon Emissions and Regional Carbon Emissions Reduction Strategies in China

Round 1

Reviewer 1 Report

The manuscript reports on agricultural carbon emissions and regional carbon emissions reduction strategies in China

line 193-195 states 'The emissions include the CH4 emissions caused by intestinal fermentation of livestock and poultry, and the CH4 and N2O emissions (in this paper, only the CH4 emissions have been taken into consideration) during the manure treatment.' - can a brief explanation for the omission of N2O emissions from manure storage be provided here with a justification for doing so.  The magnitude of N2O emissions depends on the method, can the authors provide details of the assumed manure storage methods?

line 428 'Therefore, there are four types of combinations of emission and intensity, including Low emission and Low intensity (LE&LI), Low emission and Medium intensity (LE&MI), Low emission and High intensity (LE&HI); Medium emission and Low intensity (ME&LI), Medium emission and Medium intensity (ME&MI), Medium emission and High intensity (ME&HI); High emission and Low intensity (HE&LI), High emission and Medium intensity (HE&MI), High emission and High intensity (HE&HI)' - these need some form of prioritisation attached to them rather than listing purely as the possible combinations.  For example is ME&HI more, less or equal in importance to HE&MI ? suggest these are listed in order of priority with some accompanying text to explain the reason for prioritisation.  Table 8 and section 5 should be structured such that the high priority regions / actions (e.g. HE&HI) are discussed first then the less important areas (e.g. LE&LI) are discussed last.  This brings me to my next point.  It is a discussion i.e. it needs to refer to the published literature and discuss whether e.g. experience / knowledge from published findings are in agreement / can be applied to the findings in this case study.  For example line 511 'Therefore, the agricultural carbon emissions should be reduced moderately and the intensity of carbon emissions should be controlled' - what does a moderate reduction of carbon emissions look like?  how much?  which aspects of agriculture? cattle production? cereal cropping?  how should this be managed?  e.g. the authors make reference to 'introducing the modern
agricultural industry systems such as picking industry' - by what quantity will this reduce carbon emissions?  where is the proof? i.e. needs reference to the published literature that has a validated study to substantiate this claim.  This is applicable throughout section 5. 

Author Response

Reviewer: The manuscript reports on agricultural carbon emissions and regional carbon emissions reduction strategies in China line 193-195 states 'The emissions include the CH4 emissions caused by intestinal fermentation of livestock and poultry, and the CH4 and N2O emissions (in this paper, only the CH4 emissions have been taken into consideration) during the manure treatment.' - can a brief explanation for the omission of N2O emissions from manure storage be provided here with a justification for doing so.  The magnitude of N2O emissions depends on the method, can the authors provide details of the assumed manure storage methods? Author: Thank you for your question. As for brief explanation for the omission of N2O emissions, we have read some literatures about the measurement of N2O emissions, but the main topic of this paper is the carbon emissions. If you are interested in this topic, you can contact the first author of this article for further discussion. Thank you for your comments. We have added the explanation in this paper (Line 212-218), “According to the United Nations Intergovernmental Panel on Climate Change (IPCC) and the greenhouse gas accounting method in China's “Guidelines for the Preparation of Provincial Greenhouse Gas Inventories (Trial)”, the N2O in the atmosphere mainly comes from the agricultural land, animal manure management, and waste water treatment processes of the waste treatment sector. Among which, more than 70% of nitrogen emissions come from agricultural production. Since this paper is about the agricultural carbon emissions, N2O emissions has not been measured.” For the details of the assumed manure storage methods, you can read the following papers: (1) If you are interested in the measurement of N2O emissions, you can read the following papers: Jin V L, Schmer M R, Stewart C E, et al. Management controls the net greenhouse gas outcomes of growing bioenergy feedstocks on marginally productive croplands[J]. Science Advances, 2019, 5(12): eaav9318. Keeler B L, Gourevitch J D, Polasky S, et al. The social costs of nitrogen[J]. Science advances, 2016, 2(10): e1600219. Robertson G P, Paul E A, Harwood R R. Greenhouse gases in intensive agriculture: contributions of individual gases to the radiative forcing of the atmosphere[J]. Science, 2000, 289(5486): 1922-1925. Almaraz M, Bai E, Wang C, et al. Agriculture is a major source of NOx pollution in California[J]. Science advances, 2018, 4(1): eaao3477. Yu C, Huang X, Chen H, et al. Managing nitrogen to restore water quality in China[J]. Nature, 2019, 567(7749): 516-520. (2) If you are interested in the N2O emissions in China, you can read the following papers: Li C, Frolking S, Xiao X, et al. Modeling impacts of farming management alternatives on CO2, CH4, and N2O emissions: A case study for water management of rice agriculture of China[J]. Global Biogeochemical Cycles, 2005, 19(3). Gao B, Ju X, Su F, et al. Nitrous oxide and methane emissions from optimized and alternative cereal cropping systems on the North China Plain: A two-year field study[J]. Science of the Total Environment, 2014, 472: 112-124. Luo Z, Lam S K, Fu H, et al. Temporal and spatial evolution of nitrous oxide emissions in China: Assessment, strategy and recommendation[J]. Journal of cleaner production, 2019, 223: 360-367. Reviewer: line 428 'Therefore, there are four types of combinations of emission and intensity, including Low emission and Low intensity (LE&LI), Low emission and Medium intensity (LE&MI), Low emission and High intensity (LE&HI); Medium emission and Low intensity (ME&LI), Medium emission and Medium intensity (ME&MI), Medium emission and High intensity (ME&HI); High emission and Low intensity (HE&LI), High emission and Medium intensity (HE&MI), High emission and High intensity (HE&HI)' - these need some form of prioritisation attached to them rather than listing purely as the possible combinations.  For example is ME&HI more, less or equal in importance to HE&MI ? suggest these are listed in order of priority with some accompanying text to explain the reason for prioritisation.  Author: Thank you for your suggestion. We have modified the paper. “The agricultural production and livestock products are good outputs, while agricultural carbon emissions are bad outputs. The lower the intensity of agricultural carbon emissions is, the less carbon emissions of agricultural production per unit is. Therefore, Low emission and Low intensity (LE&LI) tends to be the best combination.” (Line 471-Line 475) Reviewer: Table 8 and section 5 should be structured such that the high priority regions / actions (e.g. HE&HI) are discussed first then the less important areas (e.g. LE&LI) are discussed last.  This brings me to my next point.  Author: Thank you for your suggestion. We have made a table to explain the results, and in order to make it easier to understand, different carbon emissions and intensity of carbon emissions are shown in different colors (“red” represents high carbon emissions and intensity of carbon emissions, “yellow” represents medium carbon emissions and intensity of carbon emissions, and “green” represents low carbon emissions and intensity of carbon emissions). Reviewer: It is a discussion i.e. it needs to refer to the published literature and discuss whether e.g. experience / knowledge from published findings are in agreement / can be applied to the findings in this case study. For example line 511 'Therefore, the agricultural carbon emissions should be reduced moderately and the intensity of carbon emissions should be controlled' - what does a moderate reduction of carbon emissions look like?  how much?  which aspects of agriculture? cattle production? cereal cropping?  how should this be managed?  e.g. the authors make reference to 'introducing the modern agricultural industry systems such as picking industry' - by what quantity will this reduce carbon emissions?  where is the proof? i.e. needs reference to the published literature that has a validated study to substantiate this claim.  This is applicable throughout section 5.  Author: Thank you for your suggestion. We searched in Google with “China; Economic zone; Agricultural Carbon Emission” as key words, and we found the following papers: in Agricultural Carbon Emissions in China: Calculation, Spatial-Temporal Comparison and Decoupling Effects, the conclusions showed that, ”Compared with Tian’s (2012) conclusions [52], in China, the intensity of agricultural carbon emissions declined from the west to the east (Figure 3), and in 2016, the intensity of agricultural carbon emissions showed a trend of Northwest region > Middle reaches the Yangtze River> Northeast region > Southwest region > Northern Coast > Eastern coast > Southern coast, which has been of strong similarity with previous literatures.” As for the the review suggestion about section 5, the author have attached the data of each province at the back of this article for the convenience of the readers. This paper tends to make clear of the status of each region and provide scientific and technological support for cooperative emission reduction, so there is not too much explanation. You can contact the first author of this paper for further discussion if you are interested in this problem. What’s more, since Part 5 is the conclusion of this paper, there are not too much literature review.

Author Response File: Author Response.docx

Reviewer 2 Report

As I began to read this, aware of the many confusions in literature on this subject, I was dismayed that the basic assumptions and definitions were not laid out.  I had to search for half an hour to guess that "carbon" meant carbon atoms, and not just the common gasses that have carbon.  I am still not sure if emissions from different molecules are rationalized to aggregate the carbon atoms.  eg, how is the carbon in CO2 and CH4 treated?  

I was also perplexed at the sources and handling of raw data.  Reference 37 is crucial and I retrieved and studied that.  The data in the reference was solely for Jilin Province but then seems to be applied in the paper to 31 provinces/regions.  I am also mystified why the text covers rice cultivation but not other major crops.

I spent considerable time trying to follow the calculation of equation (1) on Line 179 wondering how data in kg and hectares were aggregated.

There are small strange twists of English such as Line 33 when a number is said to be "between" 10 and "more than" 100.  Just another exmpla Line 568 "help" should be "helped". 

Author Response

Reviewer:

As I began to read this, aware of the many confusions in literature on this subject, I was dismayed that the basic assumptions and definitions were not laid out.  I had to search for half an hour to guess that "carbon" meant carbon atoms, and not just the common gasses that have carbon.  I am still not sure if emissions from different molecules are rationalized to aggregate the carbon atoms.  eg, how is the carbon in CO2 and CH4 treated?  

Author:

Thank you for your question. Well, as to “how is the carbon in CO2 and CH4 treated”, we used the carbon emission factors, take CH₄ as example, its carbon emission factors are shown in Table 2.

Table 2. Carbon emission factors of rice cultivation in different provinces.

Province	Emission Factors(g/m2)	Province	Emission Factors(g/m2)	Province	Emission Factors(g/m2)
Beijing	13.23	Anhui	31.91	Sichuan	16.91
Tianjin	11.34	Fujian	34.62	Guizhou	16.12
Hebei	15.33	Jiangxi	42.2	Yunnan	5.73
Shanxi	6.62	Shandong	21.02	Tibet	6.83
Inner Mongolia	8.93	Henan	17.85	Shanxi	12.51
Liaoning	9.24	Hubei	38.23	Gansu	6.83
Jilin	5.57	Hunan	35.01	Qinghai	0
Heilongjiang	8.31	Guangdong	41.22	Ningxia	7.35
Shanghai	31.26	Guangxi	36.44	Xinjiang	10.52
Jiangsu	32.4	Hainan	38.43
Zhejiang	35.6	Chongqing	16.91

 

Reviewer:

I was also perplexed at the sources and handling of raw data.  Reference 37 is crucial and I retrieved and studied that.  The data in the reference was solely for Jilin Province but then seems to be applied in the paper to 31 provinces/regions.  I am also mystified why the text covers rice cultivation but not other major crops.

Author:

Thank you for taking so many time to read relavite reference, here, as we do our study based on literature from home and aboard. If you are interesting in this topic, we recommend following literature, also, these references are in our list.

Reference 11: He Y, Chen R, Wu H, Xu J, Song Y. Spatial dynamics of agricultural carbon emissions in China and the related driving factors. Chinese J Eco-Agriculture 2018;26:1269–82. https://doi.org/10.13930/j.cnki.cjea.171097.

Reference 17: Gao M., Song H. Dynamic Changes and Spatial Agglomeration Analysis of the Chinese Agricultural Carbon Emissions Performance. Economic Geography. 2015:142–148+185.

Reference 23: Zou Y, Wei N, Chen F, Tang Q, Wang L. The regional differences of carbon emission in China. World Autom. Congr. Proc., 2012.

Reference 27: Zhang G., Wang S. China's Agricultural Carbon Emission: Structure, Efficiency and Its Determinants. Issues in Agricultural Economy. 2014:18–26+110.

Reference 52: Tian Y, Zhang J B, Li B. Agricultural carbon emissions in China: calculation, spatial-temporal comparison and decoupling effects. Resources Science, 2012, 34(11): 2097-2105.

Also, our calculation method come from these references

 

Reviewer:

I spent considerable time trying to follow the calculation of equation (1) on Line 179 wondering how data in kg and hectares were aggregated.

Author:

Thank you for your question. We have calculated according to the Emission factors (Table 1), you can send email to the first author of this paper if you are interested.

Table 1. Emission factors of different carbon emission sources in land use.

Sources	Emission Factors	References
Fertilizer	0.8956kg(C)/kg	[37-39]
Pesticide	4.9341kg(C)/kg	[37][40-41]
Agricultural plastic films	5.18kg(C)/kg	[42-45]
Diesel fuel Sowing	0.5927kg(C)/kg	[5]
Irrigation	266.48kg(C)/hm2	[46-49]

 

Reviewer:

There are small strange twists of English such as Line 33 when a number is said to be "between" 10 and "more than" 100.  Just another exmpla Line 568 "help" should be "helped".

Author:

Thank you. We double check the whole paper and correct relative misleading sentence.

Reviewer 3 Report

The paper deals with GHG emissions from agriculture and provides GHG emission reduction strategies for different China regions. The paper is in the scope of Sustainability. It can be published after revision. My main recommendations are provided bellow. The novelty and input of paper   should be highlighted in introduction. The strengths and limits of applied approach should be defined in comparison with other approaches. The discussion section is missing. The results should be compared and discussed with results of other studies dealing with GHG emissions assessments in China. The sources for all tables should be provided. It is not clear how emission factors are obtained in table 3. The limitations of this study and future research guidelines need to be provided in the conclusions section.

Author Response

Reviewer:

he paper deals with GHG emissions from agriculture and provides GHG emission reduction strategies for different China regions. The paper is in the scope of Sustainability. It can be published after revision. My main recommendations are provided bellow. The novelty and input of paper should be highlighted in introduction.

Author:

Thank you for your suggestion. We add this part in the introduction part (Line 166-170)

 

Reviewer:

The strengths and limits of applied approach should be defined in comparison with other approaches.

Author

Thank you for your suggestion. We add this part in Conclusions and Discussion part

 

Reviewer:

The discussion section is missing.

Author

Thank you for your suggestion. We have this part(Line 577-581) and add this part in Section 6

 

Reviewer:

The results should be compared and discussed with results of other studies dealing with GHG emissions assessments in China.

Author

Thank you for your suggestion. We searched in Google with “China; Economic zone; Agricultural Carbon Emission” as key words, and we found the following papers:

 

in Agricultural Carbon Emissions in China: Calculation, Spatial-Temporal Comparison and Decoupling Effects, the conclusions showed that, ”Compared with Tian’s (2012) conclusions [52], in China, the intensity of agricultural carbon emissions declined from the west to the east (Figure 3), and in 2016, the intensity of agricultural carbon emissions showed a trend of Northwest region > Middle reaches the Yangtze River> Northeast region > Southwest region > Northern Coast > Eastern coast > Southern coast, which has been of strong similarity with previous literatures.”

 

 

 

Reviewer:

The sources for all tables should be provided.

Author:

Thank you for your suggestion. Table 1-3 come from literature, We add this part from table 4, table 5 and table 6.

 

 

Reviewer:

It is not clear how emission factors are obtained in table 3.

Author:

Thank you for pointing it out. We add the literature.

 

Reviewer:

The limitations of this study and future research guidelines need to be provided in the conclusions section.

Author:

Thank you. We add this part (line 578-582)

 

Reviewer 4 Report

The main purpose of this paper is to measure the total amount and the intensity of agricultural carbon emission in China, and to compare the regional differences of agricultural carbon emissions with the method of coefficient of variation and the Theil index. The results show that total carbon emission in 2016 was 272.022 million tons with an average annual increase of 1.67%. This paper has finally provided supports for the reduction of agricultural carbon emissions in China based on the matrix of carbon emission reducing strategies.

This is an interesting paper which makes contributions towards related literature. I list my comments as follows.

1. The authors try to use some measures to represent the total amount and the intensity of agricultural carbon emission. It is the great contribution of this research. However, you don’t analyze what factors, such as regional characteristics, would influence total amount and the intensity of agricultural carbon emission. You show the situation of agricultural carbon emission in China but don’t provide the sufficient evidence to support your reduction strategies.
2. This research applies historical data to analyze carbon emissions in eight economic zones and suggests policy recommendations for the reduction of regional agricultural carbon emissions based on those results, but it doesn’t use any way to predict carbon emissions in the future. Would policy recommendations be reliable without predicting?
3. The authors should describe the equations and data more clearly. Although this study provides emission factors in Table 1, you don’t explain how to calculate E_fe, E_pe, E_pl, E_ga, E_so and E_ir in detail.
4. In Line 428, I don’t understand why the paper states that there are “four” types of combinations of emission and intensity?
5. There are a lot of gramma errors. I suggest the authors to recheck your manuscript carefully.

I hope that my comments will help the authors to improve the quality of the paper.

Author Response

Reviewer:

The main purpose of this paper is to measure the total amount and the intensity of agricultural carbon emission in China, and to compare the regional differences of agricultural carbon emissions with the method of coefficient of variation and the Theil index. The results show that total carbon emission in 2016 was 272.022 million tons with an average annual increase of 1.67%. This paper has finally provided supports for the reduction of agricultural carbon emissions in China based on the matrix of carbon emission reducing strategies.

This is an interesting paper which makes contributions towards related literature. I list my comments as follows.

The authors try to use some measures to represent the total amount and the intensity of agricultural carbon emission. It is the great contribution of this research. However, you don’t analyze what factors, such as regional characteristics, would influence total amount and the intensity of agricultural carbon emission. You show the situation of agricultural carbon emission in China but don’t provide the sufficient evidence to support your reduction strategies.

Author:

Thank you for your question. This paper tends to analyze the regional agricultural production based on the total agricultural carbon emissions and the intensity of carbon emissions, so as to provide recommendations for carbon reduction in different regions. The conclusions of this paper have been drawn according to the combination of the total agricultural carbon emissions and the intensity of carbon emissions, and the policy recommendations have been jointly discussed by the authors of this paper.

 

Reviewer:

This research applies historical data to analyze carbon emissions in eight economic zones and suggests policy recommendations for the reduction of regional agricultural carbon emissions based on those results, but it doesn’t use any way to predict carbon emissions in the future. Would policy recommendations be reliable without predicting?

Author:

Thank you for your question. Some policy recommendations in this paper have been provided on the basis of following literatures:

Reference 11: He Y, Chen R, Wu H, Xu J, Song Y. Spatial dynamics of agricultural carbon emissions in China and the related driving factors. Chinese J Eco-Agriculture 2018;26:1269–82. https://doi.org/10.13930/j.cnki.cjea.171097.

Reference 17: Gao M., Song H. Dynamic Changes and Spatial Agglomeration Analysis of the Chinese Agricultural Carbon Emissions Performance. Economic Geography. 2015:142–148+185.

Reference 23: Zou Y, Wei N, Chen F, Tang Q, Wang L. The regional differences of carbon emission in China. World Autom. Congr. Proc., 2012.

Reference 27: Zhang G., Wang S. China's Agricultural Carbon Emission: Structure, Efficiency and Its Determinants. Issues in Agricultural Economy. 2014:18–26+110.

Reference 52: Tian Y, Zhang J B, Li B. Agricultural carbon emissions in China: calculation, spatial-temporal comparison and decoupling effects. Resources Science, 2012, 34(11): 2097-2105.

 

Reviewer:

The authors should describe the equations and data more clearly. Although this study provides emission factors in Table 1, you don’t explain how to calculate Efe, Epe, Epl, Ega, Eso and Eir in detail.

Author:

Thank you for pointing it out. The carbon emissions of this paper have been calculated on the basis of relevant literatures, and the results have been obtained by multiplying the amount of consumption and the emission coefficient.

 

Reviewer:

In Line 428, I don’t understand why the paper states that there are “four” types of combinations of emission and intensity?

Author:

Thank you for pointing it out. We correct it, here should be nine

 

Reviewer:

There are a lot of gramma errors. I suggest the authors to recheck your manuscript carefully.

Author:

Thank you. We send this paper to an English proofing

 

Reviewer:

I hope that my comments will help the authors to improve the quality of the paper.

Author:

Thank you very much for your suggestion

 

Round 2

Reviewer 1 Report

original comment: The magnitude of N2O emissions depends on the method, can the authors provide details of the assumed manure storage methods?

Author: Thank you for your question. As for brief explanation for the omission of N2O emissions, we have read some literatures about the measurement of N2O emissions, but the main topic of this paper is the carbon emissions. If you are interested in this topic, you can contact the first author of this article for further discussion. 

I find it puzzling that N2O emissions are not included since they have carbon dioxide equivalents and are a crucial aspect of agricultural greenhouse gas emissions.    In light of this the title needs to be changed from 'Research on Agricultural Carbon Emissions and Regional Carbon Emissions Reduction Strategies in China' to something like 'Research on Agricultural Carbon Dioxide and Methane Emissions and Regional Strategies for their Reduction in China' to avoid any misconception that this may be a complete greenhouse gas study

would suggest you add a colour key for Table 8

heading 6 Discussion and Conclusions

what were Tian’s (2012) conclusions? if they are different why is this?  are there comparable studies in other countries that can be discussed? 

Author Response

Reviewer:

original comment: The magnitude of N2O emissions depends on the method, can the authors provide details of the assumed manure storage methods?

Author: Thank you for your question. As for brief explanation for the omission of N2O emissions, we have read some literatures about the measurement of N2O emissions, but the main topic of this paper is the carbon emissions. If you are interested in this topic, you can contact the first author of this article for further discussion. 

I find it puzzling that N2O emissions are not included since they have carbon dioxide equivalents and are a crucial aspect of agricultural greenhouse gas emissions. In light of this the title needs to be changed from 'Research on Agricultural Carbon Emissions and Regional Carbon Emissions Reduction Strategies in China' to something like 'Research on Agricultural Carbon Dioxide and Methane Emissions and Regional Strategies for their Reduction in China' to avoid any misconception that this may be a complete greenhouse gas study

Author:

Thank you for your suggestion. For the emission of N₂O, we searched in Google with “agricultural carbon emission China” as the key word, and we found the following papers:

 

[1] Li B, Zhang J B, Li H P. Research on spatial-temporal characteristics and affecting factors decomposition of agricultural carbon emission in China[J]. China population, resources and environment, 2011, 21(8): 80-86.

Characteristics of agricultural carbon emission: have not measured the emission of N₂O.

[2] Tian Y, Zhang J B, Li B. Agricultural carbon emissions in China: calculation, spatial-temporal comparison and decoupling effects[J]. Resources Science, 2012, 34(11): 2097-2105.

Characteristics of agricultural carbon emission: have not measured the emission of N₂O.

[3] Tian Y, Zhang J B, He Y Y. Research on spatial-temporal characteristics and driving factor of agricultural carbon emissions in China[J]. J. Integr. Agric, 2014, 13(6): 1393.

Characteristics of agricultural carbon emission: measured the carbon emission of animals and calculated the conversion factors of CH₄ and N₂O.

[5] Li B, Zhang J, Li H. Empirical study on China's agriculture carbon emissions and economic development [J]. Journal of Arid Land Resources and Environment, 2011, 12(001).

Characteristics of agricultural carbon emission: have not measured the emission of N₂O.

 [6] RAN G, WANG J, WANG D. Study on the Changing Tendency and Counter-measures of Carbon Emission Produced by Agricultural Production in China [J]. Issues in Agricultural Economy, 2011, 2: 32.

Characteristics of agricultural carbon emission: have not measured the emission of N₂O.

 [7] Xiong C, Yang D, Huo J. Spatial-temporal characteristics and LMDI-based impact factor decomposition of agricultural carbon emissions in Hotan Prefecture, China[J]. Sustainability, 2016, 8(3): 262.

Characteristics of agricultural carbon emission: measured the carbon emission of animals and calculated the conversion factors of CH₄ and N₂O.

 [8] Luo Y, Long X, Wu C, et al. Decoupling CO2 emissions from economic growth in agricultural sector across 30 Chinese provinces from 1997 to 2014[J]. Journal of Cleaner Production, 2017, 159: 220-228.

Characteristics of agricultural carbon emission: have not measured the emission of N₂O.

The carbon emission of N₂O has not been taken into consideration in this paper, since the measurement of carbon emission of N₂O has not been standardized in existing literatures. We have modified the paper and made an explanation in discussion (Line 586-587).

 

 

 

Reviewer:

would suggest you add a colour key for Table 8

Author:

Thank you for your suggestion. We add the key below this table (Line 451-452).

Reviewer:

heading 6 Discussion and Conclusions

what were Tian’s (2012) conclusions? if they are different why is this?  are there comparable studies in other countries that can be discussed? 

Author:

Reference: Tian Y, Zhang J B, Li B. Agricultural carbon emissions in China: calculation, spatial-temporal comparison and decoupling effects. Resources Science, 2012, 34(11): 2097-2105.

Compared with Tian’s (2012) conclusions [52], in China, the intensity of agricultural carbon emissions declined from the west to the east (Figure 3), and in 2016, the intensity of agricultural carbon emissions showed a trend of Northwest region > Middle reaches the Yangtze River> Northeast region > Southwest region > Northern Coast > Eastern coast > Southern coast, which has been of strong similarity with previous literatures.”

 

 

Tian’s conclusions are consistent with ours, which can be strong support for our research.

As for the question “are there comparable studies in other countries that can be discussed?” we have studied the agricultural carbon emissions in BRICS, Nepal, Pakistan and French, and we found that there are not too many researches on regional carbon emissions, whose marginal contribution can be of great significance.

[1] Balsalobre-Lorente D, Driha O M, Bekun F V, et al. Do agricultural activities induce carbon emissions? The BRICS experience[J]. Environmental Science and Pollution Research, 2019, 26(24): 25218-25234.

[2] Adhikari S, Mahapatra P S, Sapkota V, et al. Characterizing emissions from agricultural diesel pumps in the Terai region of Nepal[J]. Atmosphere, 2019, 10(2): 56.

[3] Rehman A, Ozturk I, Zhang D. The causal connection between CO2 emissions and agricultural productivity in Pakistan: empirical evidence from an autoregressive distributed lag bounds testing approach[J]. Applied Sciences, 2019, 9(8): 1692.

[4] Garnier J, Le Noë J, Marescaux A, et al. Long-term changes in greenhouse gas emissions from French agriculture and livestock (1852–2014): From traditional agriculture to conventional intensive systems[J]. Science of The Total Environment, 2019, 660: 1486-1501.

Reviewer 3 Report

The paper was corrected. The authors did all necessary corrections and addressed my comments. The authors have provided answers to all comments. The paper can be published in current form.

Author Response

Thank you so much.

Best!

Round 3

Reviewer 1 Report

for future reference i would advise including the carbon equivalents of N2O in any agricultural greenhouse gas assessment

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript evaluates trends in carbon emissions from agriculture in China for the period 2000 - 2016.  The comments below aim to be constructive.

 

Abstract line 13 and throughout document: need to clarify what is meant by 'intensity of agricultural carbon emissions' - is this on a per unit area basis i.e. per ha? in which case this needs to be clarified

Table 1. the emission factor is per kg of fertiliser - which type?  there is a considerable difference between nitrate based fertilisers and those containing phosphate or potassium.  Nitrogen fertilsers tend to be the greatest contributors to agricultural greenhouse gas emissions, this needs to be emphasised if it is the case here.

section 2.1.3 Carbon emission from ruminant animals - poultry are not ruminants.  line 201 states 'important source of agricultural carbon emissions, which consist of two parts: one is the CH4 emissions caused by intestinal fermentation of livestock and poultry;' poultry tend not to contribute significantly to enteric fermentation, indeed this is stated in Table 3 where poultry are assigned a value of zero.  why is it then highlighted as a key emission source in the text.  the legend of Table 3 'Carbon emission factors of different ruminant animals' needs amending, pigs and poultry are not ruminants.

Table 4. 'Amount and composition of agricultural carbon emission from 2000 to 2016 (10,000-ton,' by ton is it metric tonnes?  a ton is an imperial ton which is a different unit.  check spelling.  For an international journal SI units should be used i.e. metric tonnes

line 273 'As a whole, the agricultural carbon emissions increased greatly from 2000 to 2016' - is this due to changes in land use e.g. increase in agricultural land use or is it due to a change in management e.g. increased application of nitrogen fertiliser or stocking rates?  in which case the emissions per unit area i.e. per ha added to Table 4 would be useful to identify which is happening.

The figures all require improvement.  Fundamental requirements which I would expect at high school level include the use of axes titles for both X and Y axes e.g. no X axis label in Figure 2, 14 etc.  The graphs need to be consistently formatted.  There appears to be issues with the labels not being in English for some figures.   This should have been checked before submission of the manuscript rather than copying and pasting images from the original version.  The legends for each figure / table need to be 'stand-alone' so the reader knows what they represent without having to delve into the text. 

Table 8 - what is the purpose of this?  it states the obvious.  it would be better if a scoring approach was adopted e.g. low = 1, medium = 2, high = 3 then multiply each score so low x low = 1 overall, high x high = 9.  The overly large and cumbersome table 9 would then be easy to extract information from as it would contain numbers not text.  if the authors choose not to use this approach i would suggest both table are removed as they do not add anything.

Sections 5.1. to 5.8 - suggest this is summarised into a single heading and the priorities are reported i.e. which zones in descending order of importance with reasons and suggestions for emissions reduction with reference to the published literature.  At present is more of a list.

I suggest the title 'Research on Agricultural Carbon Emissions and Regional Carbon Emissions Reduction Strategies in China' is modified to 'Agricultural Carbon Emissions and Regional Carbon Emissions in China' since as far as i can see the manuscript reports on trends in emissions rather than emissions reduction strategies. 

Author Response

Reviewer:

Abstract line 13 and throughout document: need to clarify what is meant by 'intensity of agricultural carbon emissions' - is this on a per unit area basis i.e. per ha? in which case this needs to be clarified

Author:

Thank you for your question. In this paper, intensity of agricultural carbon emissions means agricultural carbon emission per capital, in order to make it more readable to reader, we add this information in our Abstract part( Page 1, line 14)

 

Reviewer:

Table 1. the emission factor is per kg of fertiliser - which type?  there is a considerable difference between nitrate based fertilisers and those containing phosphate or potassium.  Nitrogen fertilsers tend to be the greatest contributors to agricultural greenhouse gas emissions, this needs to be emphasised if it is the case here.

Author:

Thank you for your suggestion. The agricultural greenhouse gas emissions can be affected by the type of fertilisers, but the data used in this paper are collected from China Statistical Yearbook (http://www.stats.gov.cn/tjsj/ndsj/2017/indexch.htm), where the fertilisers have not been classified. This problem has been explained in discussion, which can be solved in further studies.

 

Reviewer:

section 2.1.3 Carbon emission from ruminant animals - poultry are not ruminants.  line 201 states 'important source of agricultural carbon emissions, which consist of two parts: one is the CH4 emissions caused by intestinal fermentation of livestock and poultry;' poultry tend not to contribute significantly to enteric fermentation, indeed this is stated in Table 3 where poultry are assigned a value of zero.  why is it then highlighted as a key emission source in the text.  the legend of Table 3 'Carbon emission factors of different ruminant animals' needs amending, pigs and poultry are not ruminants.

Author:

Thank you for your question. The crops in this paper are classified according previous researches, and the specification of ”poultry are assigned a value of zero” has also been defined according to the parameters of existing references.

1) For the first question, according to previous researches, the pigs and sheep are major carbon emission sources.

2) We have revised the paper according to the second suggestion.

 

Reviewer:

Table 4. 'Amount and composition of agricultural carbon emission from 2000 to 2016 (10,000-ton,' by ton is it metric tonnes?  a ton is an imperial ton which is a different unit.  check spelling.  For an international journal SI units should be used i.e. metric tonnes

Author:

Thank you for pointing it out. The carbon emissions in this paper were calculated by metric tonnes.

Reviewer:

line 273 'As a whole, the agricultural carbon emissions increased greatly from 2000 to 2016' - is this due to changes in land use e.g. increase in agricultural land use or is it due to a change in management e.g. increased application of nitrogen fertiliser or stocking rates?  in which case the emissions per unit area i.e. per ha added to Table 4 would be useful to identify which is happening.

Author:

Thank you for your suggestion. The agricultural carbon emission can be affected by many factors, including environment, economy and society. Since this paper is about the inter-regional interactions, we have not studied the key influencing factors and the influence path. This paper can provide references for further studies.

 

Reviewer:

The figures all require improvement.  Fundamental requirements which I would expect at high school level include the use of axes titles for both X and Y axes e.g. no X axis label in Figure 2, 14 etc.  The graphs need to be consistently formatted.  There appears to be issues with the labels not being in English for some figures.   This should have been checked before submission of the manuscript rather than copying and pasting images from the original version.  The legends for each figure / table need to be 'stand-alone' so the reader knows what they represent without having to delve into the text. 

Author:

Thank you for your suggestion. We have made the changes accordingly.

 

Reviewer:

Table 8 - what is the purpose of this?  it states the obvious.  it would be better if a scoring approach was adopted e.g. low = 1, medium = 2, high = 3 then multiply each score so low x low = 1 overall, high x high = 9.  The overly large and cumbersome table 9 would then be easy to extract information from as it would contain numbers not text.  if the authors choose not to use this approach i would suggest both table are removed as they do not add anything.

Author:

Thank you for pointing it out. We have deleted Table 8 and simplified Table 9, and the policy recommendations have been adjusted accordingly.

 

Reviewer:

Sections 5.1. to 5.8 - suggest this is summarised into a single heading and the priorities are reported i.e. which zones in descending order of importance with reasons and suggestions for emissions reduction with reference to the published literature.  At present is more of a list.

Author:

Thank you for your suggestion. This paper is about to provide recommendations for different regions, so we divided the recommendations into eight parts. What’s more, after reading existing references, we have found that there are few regional researches, so we conducted the research at the regional level.

[1] Li, Bo, J. B. Zhang, and H. P. Li. "Research on spatial-temporal characteristics and affecting factors decomposition of agricultural carbon emission in China." China population, resources and environment 21.8 (2011): 80-86.

[2] Xiong C, Yang D, Xia F, et al. Changes in agricultural carbon emissions and factors that influence agricultural carbon emissions based on different stages in Xinjiang, China[J]. Scientific reports, 2016, 6: 36912.

[3] Zhang L, Pang J, Chen X, et al. Carbon emissions, energy consumption and economic growth: Evidence from the agricultural sector of China's main grain-producing areas[J]. Science of the Total Environment, 2019, 665: 1017-1025.

[4] Huang X, Xu X, Wang Q, et al. Assessment of Agricultural Carbon Emissions and Their Spatiotemporal Changes in China, 1997–2016[J]. International journal of environmental research and public health, 2019, 16(17): 3105.

[5] Tian Y, Zhang J B, Li B. Agricultural carbon emissions in China: calculation, spatial-temporal comparison and decoupling effects[J]. Resources Science, 2012, 34(11): 2097-2105.

 

Reviewer:

I suggest the title 'Research on Agricultural Carbon Emissions and Regional Carbon Emissions Reduction Strategies in China' is modified to 'Agricultural Carbon Emissions and Regional Carbon Emissions in China' since as far as i can see the manuscript reports on trends in emissions rather than emissions reduction strategies. 

Author:

Thank you for your suggestion. We put some regional agricultural carbon emission reduction strategies in part 5 (Line 423-Line 531).

Reviewer 2 Report

This paper focuses on the agricultural carbon emissions and strategies of the regional carbon emissions reduction in China. Below please find my comments.

 

At first, based on the instruction of MDPI and Sustainability, the Abstract section should give a pertinent overview of the work and indicate the main conclusions or interpretations. Most of the original content in this part basically moves over the conclusion section in line 529-551.

Also, in the introduction part, in line 38-39, the land use in IPCC is not equal to the agricultural land use mentioned in the paper. Words need to be more accurate. It is also suggested to make a more comprehensive literature review for this paper. I may not agree with the description in Line 173-174.

 

Furthermore, the section 2, method and data, requires major improvements.

(1) The data source should be clarified clearly.

(2) In line 181-187, it is too simple to choose calculation factors of carbon emission only by referring to three literatures.

(3) The reason and logic for calculation the carbon emissions from rice cultivation should be clear in the following section 2.1.2.

(4) Most of the methods comes from only one reference ([27]) is not reasonable for this paper.

All the results are based on the data and methods. Therefore, it is recommended to be more cautious and serious about methods and data.

 

Finally, the tables and figures could be modified. For example, Table 9 takes up nearly two pages. However, the “Medium emissions & medium intensity” can be replaced by abbreviation “ME&MI” to reduce the useless description. And language needs to be improved later, especially for important descriptions and conclusions (i.e. line 14-15, 37-38, et al.).

Author Response

This paper focuses on the agricultural carbon emissions and strategies of the regional carbon emissions reduction in China. Below please find my comments.

Reviewer:

At first, based on the instruction of MDPI and Sustainability, the Abstract section should give a pertinent overview of the work and indicate the main conclusions or interpretations. Most of the original content in this part basically moves over the conclusion section in line 529-551.

Author:

Thank you for your suggestion. We made the changes accordingly.

 

Reviewer:

Also, in the introduction part, in line 38-39, the land use in IPCC is not equal to the agricultural land use mentioned in the paper. Words need to be more accurate. It is also suggested to make a more comprehensive literature review for this paper. I may not agree with the description in Line 173-174.

Author:

Thank you for your question. The agricultural land use is only one part of land use mentioned in IPCC, here, we would like to emphasize that the carbon emission can be affected by the agricultural production activities.

We have added 40 references so as to make a more comprehensive literature review.

For Line 173-174 ”It can be seen that, the existing researches on agricultural carbon emissions are mainly conducted at the provincial level rather than the regional level”, we would like to emphasize the importance of analyzing the regional agricultural carbon emission.

 

Reviewer:

Furthermore, the section 2, method and data, requires major improvements.

(1) The data source should be clarified clearly.

Author:

Thank you for your suggestion. We have explained the data source, and uploaded the raw data.

 

Reviewer:

(2) In line 181-187, it is too simple to choose calculation factors of carbon emission only by referring to three literatures.

Author:

Thank you for pointing it out. There are great differences between difference papers, we have chosen 3 representative papers and revised our paper.

 

Reviewer:

(3) The reason and logic for calculation the carbon emissions from rice cultivation should be clear in the following section 2.1.2.

Author:

Thank you for your question. The carbon emission of crop cultivation has been calculated according to the FAO standard (http://www.fao.org/faostat/zh/#data).

 

Reviewer:

(4) Most of the methods comes from only one reference ([27]) is not reasonable for this paper.

All the results are based on the data and methods. Therefore, it is recommended to be more cautious and serious about methods and data.

Author:

Thank you for pointing it out. There are great differences between difference papers, we have chosen one representative paper and revised our paper.

 

Reviewer:

Finally, the tables and figures could be modified. For example, Table 9 takes up nearly two pages. However, the “Medium emissions & medium intensity” can be replaced by abbreviation “ME&MI” to reduce the useless description. And language needs to be improved later, especially for important descriptions and conclusions (i.e. line 14-15, 37-38, et al.).

Author:

Thank you for your kindly help. We have made the changes accordingly. Also, the language has sent to an original speaker.

Reviewer 3 Report

The manuscript deals with an actual topic. The investigation of the Chinese agriculture is an always actual topic because China is the most populated country in the whole world. China – just like the other countries laying on large territories – has several agricultural regions with own profiles. Analysing the circumstances of these agricultural regions is crucial because of the agro-economic impact of China on the global market.

We can also mention this circumstance as a weakness of the manuscript. However the authors pay attention for several impacts they do not deal with the following topics:

The future perspectives of food consumption in China. Can China produce enough food for its citizens or not? If not, from where can China import enough food for the population? This part is strongly connected to the number of population in China and their spatial distribution in the country. The distance between the production and consumption places. China is a very large country where the population mostly concentrated on the coastal areas of Eastern China. Chinese famers and agricultural companies have to transport the produced food from the rural areas to the urban zones. The authors should also pay attention for this circumstance in their analysis. Possibilities of technological shifts in the agricultural production. Is there any possibility to implement technological innovations in the agricultural production? If there is any available innovation what kind of effect will it have on the level of production? The increasing level of consumption (because the larger population needs more food and the more wealthy population will consume more meat and dairy products and this circumstance have an effect on the crop production as well) will also have effects on the agricultural production. Are the alternative agricultural production suitable to produce enough – and more than enough – food? The authors also have to pay attention for the environmental impacts of the possible technological changes because if the potential outcome of the different reforms is not suitable enough or the planned technological shifts are able to cause harm for the people we also have to count with these circumstances.

The authors should pay more attention for the potential non-Chinese readers of their publication. While reading the manuscript I detected several weaknesses of the figures edited by the authors. Hereby I list all the errors I detected during the preparation of the review of the mentioned manuscript:

Figures 1, 2, 3, 4, 5, 6 are totally not understandable because all the information they contain is written in Chinese. Figure No. 14 comes after Figure No. 6 but where are Figures Nos. 7-13?

The English language use of the manuscript is acceptable in its present form.

The authors of the manuscript should cite more authors – and more non-Chinese authors in order to extend the international focus of the literature review part of the article. I strongly recommend to cite international articles in the topics I mentioned above: these global topics are often investigated by international researchers as well.

 

Author Response

The manuscript deals with an actual topic. The investigation of the Chinese agriculture is an always actual topic because China is the most populated country in the whole world. China – just like the other countries laying on large territories – has several agricultural regions with own profiles. Analysing the circumstances of these agricultural regions is crucial because of the agro-economic impact of China on the global market.

We can also mention this circumstance as a weakness of the manuscript. However the authors pay attention for several impacts they do not deal with the following topics:

Reviewer:

The future perspectives of food consumption in China. Can China produce enough food for its citizens or not? If not, from where can China import enough food for the population? This part is strongly connected to the number of population in China and their spatial distribution in the country. The distance between the production and consumption places. China is a very large country where the population mostly concentrated on the coastal areas of Eastern China. Chinese famers and agricultural companies have to transport the produced food from the rural areas to the urban zones. The authors should also pay attention for this circumstance in their analysis. Possibilities of technological shifts in the agricultural production. Is there any possibility to implement technological innovations in the agricultural production? If there is any available innovation what kind of effect will it have on the level of production? The increasing level of consumption (because the larger population needs more food and the more wealthy population will consume more meat and dairy products and this circumstance have an effect on the crop production as well) will also have effects on the agricultural production. Are the alternative agricultural production suitable to produce enough – and more than enough – food? The authors also have to pay attention for the environmental impacts of the possible technological changes because if the potential outcome of the different reforms is not suitable enough or the planned technological shifts are able to cause harm for the people we also have to count with these circumstances.

Author:

Thank you for your kindly question. We have also concerned about these issues since they are international concerns, but this paper is mainly about the regional agricultural carbon emission. You can send e-mail to Associate Professor Wang, the first author of this paper, to discuss these issues if you have interests.

 

Reviewer:

The authors should pay more attention for the potential non-Chinese readers of their publication. While reading the manuscript I detected several weaknesses of the figures edited by the authors. Hereby I list all the errors I detected during the preparation of the review of the mentioned manuscript:

Figures 1, 2, 3, 4, 5, 6 are totally not understandable because all the information they contain is written in Chinese. Figure No. 14 comes after Figure No. 6 but where are Figures Nos. 7-13?

Author:

Thank you for pointing it out. We have revised the paper.

 

 

 

Reviewer:

The English language use of the manuscript is acceptable in its present form.

Author:

Thank you for your suggestion.

 

Reviewer:

The authors of the manuscript should cite more authors – and more non-Chinese authors in order to extend the international focus of the literature review part of the article. I strongly recommend to cite international articles in the topics I mentioned above: these global topics are often investigated by international researchers as well.

Author:

Thank you for your suggestion. We made the changes accordingly

 

Reviewer 4 Report

This paper focuses on agricultural carbon emissions in China. It is better to submit it to a Chinese journal after improving scientific and analytic evidence. 

Author Response

Reviewer:

This paper focuses on agricultural carbon emissions in China. It is better to submit it to a Chinese journal after improving scientific and analytic evidence. 

Author:

Thank you for your suggestion. This paper is about the agricultural carbon emission in China, but we have mainly focused on the regional cooperation in the reduction of carbon emission, with China as a case. In this paper, we have discussed how to reduce the amount and intensity of carbon emission through regional cooperation, which is essential to the global climate change, especially to the regional cooperation between different regions with different levels of development. What’s more, we believe that the experiences of China can be useful references for other countries.

Reviewer 5 Report

The main drawback of the paper "Research on Agricultural Carbon Emissions and Regional Carbon Emissions Reduction Strategies in China" is the lack of connection between policy recommendations and research results. The study shows spatial differentiation and changes in the level of GHG emissions over time. However, the reasons for this were not indicated. It was limited to short descriptions of regions and economic zones. On the other hand, the policy recommendations presented indicated the directions of changes in the nature of agricultural production.

Detailed comments:

Line 34. “Carbon emission has become a key indicator of climate change.” I would rather change the word “indicator” to “cause”. Line 46, the authors state that " With the development of modern agriculture, the use of chemical fertilizers and pesticides, and especially the agricultural machinery has led to an increase in agricultural carbon emissions." and in line 56 that " 1% of CO2 emissions are caused by the production and use of agricultural machinery, fertilizers and other chemical inputs". Line 63, it is stated that " The reasons for the reduction of agricultural carbon emissions include the improvement of land productivity". It is surprising because higher land productivity is usually associated with higher inputs of fertilizers, pesticides, etc. and consequently higher emissions of GHG. Line 184, table 1. GHG emission is associated primarily with the use of nitrogen fertilizers. Using one indicator for all kind of fertilizers can lead to significant errors. Line 212. Table 3. The values in the table show discrepancies with the source to which the authors refer. All charts require the English version. Line 289. Chart 2 and line 340. Chart 3. Such strong trends indicate that the main factor influencing the changes in the intensity of carbon emissions are changes in prices of agricultural products. This type of analysis requires the use of fixed prices, otherwise the results are very misleading. The note applies to the entire section on carbon intensity. Line 369. “With the implementation of China's rural revitalization strategy …. the agricultural carbon emissions will 370 decrease gradually.” There is no evidence in the which support such statement. Line 440. Table 9. Apart from the problem of incorrect approach to assessing carbon intensity, a better solution for presenting such information would be a three-dimensional graph. If it is needed at all.

Author Response

Reviewer:

The main drawback of the paper "Research on Agricultural Carbon Emissions and Regional Carbon Emissions Reduction Strategies in China" is the lack of connection between policy recommendations and research results. The study shows spatial differentiation and changes in the level of GHG emissions over time. However, the reasons for this were not indicated. It was limited to short descriptions of regions and economic zones. On the other hand, the policy recommendations presented indicated the directions of changes in the nature of agricultural production.

Detailed comments:

Line 34. “Carbon emission has become a key indicator of climate change.” I would rather change the word “indicator” to “cause”.

Author:

Thank you for your suggestion. We accept the suggestion and made the change accordingly.

 

Reviewer:

Line 46, the authors state that " With the development of modern agriculture, the use of chemical fertilizers and pesticides, and especially the agricultural machinery has led to an increase in agricultural carbon emissions." and in line 56 that " 1% of CO2 emissions are caused by the production and use of agricultural machinery, fertilizers and other chemical inputs". Line 63, it is stated that " The reasons for the reduction of agricultural carbon emissions include the improvement of land productivity". It is surprising because higher land productivity is usually associated with higher inputs of fertilizers, pesticides, etc. and consequently higher emissions of GHG.

Author:

Thank you for your question. More fertilizer input can bring high production, but the environment can be destroyed by the overuse of fertilizer.

 

Reviewer:

Line 184, table 1. GHG emission is associated primarily with the use of nitrogen fertilizers. Using one indicator for all kind of fertilizers can lead to significant errors.

Author:

Thank you for your suggestion. The agricultural greenhouse gas emissions can be affected by the type of fertilisers, but the data used in this paper are collected from China Statistical Yearbook (http://www.stats.gov.cn/tjsj/ndsj/2017/indexch.htm), where the fertilisers have not been classified. This problem has been explained in discussion, which can be solved in further studies.

 

Reviewer:

Line 212. Table 3. The values in the table show discrepancies with the source to which the authors refer.

Author:

Thank you for pointing it out. We add some other references.

 

 

Reviewer:

All charts require the English version.

Author:

Thank you for pointing it out. We made the changes accordingly

 

Reviewer:

Line 289. Chart 2 and line 340. Chart 3. Such strong trends indicate that the main factor influencing the changes in the intensity of carbon emissions are changes in prices of agricultural products. This type of analysis requires the use of fixed prices, otherwise the results are very misleading. The note applies to the entire section on carbon intensity.

Author:

Thank you for your kindly suggestion. The prices used in this paper have been converted according to the price in 2000, and the result of this paper is consistent with existing researches.

 

Reference: Huang X, Xu X, Wang Q, et al. Assessment of Agricultural Carbon Emissions and Their Spatiotemporal Changes in China, 1997–2016[J]. International journal of environmental research and public health, 2019, 16(17): 3105.

 

Reviewer:

Line 369. “With the implementation of China's rural revitalization strategy …. the agricultural carbon emissions will 370 decrease gradually.” There is no evidence in the which support such statement.

Author:

Thank you for pointing it out. We have revised the paper and deleted this sentence.

 

 

 

 

Reviewer:

Line 440. Table 9. Apart from the problem of incorrect approach to assessing carbon intensity, a better solution for presenting such information would be a three-dimensional graph. If it is needed at all.

Author:

Thank you for your suggestion. We have simplified Table 9 and looked forward to your suggestion.

 

Round 2

Reviewer 1 Report

revisions noted

 

Reviewer:

Table 4. 'Amount and composition of agricultural carbon emission from 2000 to 2016 (10,000-ton,' by ton is it metric tonnes?  a ton is an imperial ton which is a different unit.  check spelling.  For an international journal SI units should be used i.e. metric tonnes

Author:

Thank you for pointing it out. The carbon emissions in this paper were calculated by metric tonnes

it is still referred to as tons in the manuscript

 

 

Author Response

Reviewer: Table 4. 'Amount and composition of agricultural carbon emission from 2000 to 2016 (10,000-ton,' by ton is it metric tonnes? a ton is an imperial ton which is a different unit. check spelling. For an international journal SI units should be used i.e. metric tonnes Author: Thank you for pointing it out. The carbon emissions in this paper were calculated by metric tonnes Reviewer: it is still referred to as tons in the manuscript Author: Thank you for pointing it out. In this paper, we used the Chinese metric ton, which is easy to understand. What's more, since this paper has mainly focused on China, the potential researchers or readers may be more inclined to use Chinese metric tons for comparison.

Reviewer 2 Report

The revised manuscript has improved its quality, however some major issues still exist: 

The literature review suggests that provincial level has been studied more than regional level, why not study city level then to have a deeper and more detailed analysis? Simply combining provinces into regions with an outdated definition "the eight economic zones" (which seems to be raised more than one decade ago) without explanation for its rationale does not contribute to the literature. Study cities in some specific regions such as the Greater Bay Area may be more informative and updated. 

The discussion of results are straightforward without in-depth understanding of the literature and its contribution to filling research gaps. 

Why study agriculture emission is important to China (and maybe the world) has not been well explained. 

Author Response

Reviewer:

The revised manuscript has improved its quality, however some major issues still exist: 

The literature review suggests that provincial level has been studied more than regional level, why not study city level then to have a deeper and more detailed analysis? Simply combining provinces into regions with an outdated definition "the eight economic zones" (which seems to be raised more than one decade ago) without explanation for its rationale does not contribute to the literature. Study cities in some specific regions such as the Greater Bay Area may be more informative and updated.

Author:

Thank you for your suggestion. Although it is of great significance to conduct research at the city level, it is difficult to obtain the city data, so we conducted the research at the provincial level. For "the eight economic zones", since they are geographically adjacent and have similar agricultural productions, the policy recommendations tend to be more practical and meaningful. The Literature review has been modified, so as to explain the regional division in this paper.

 

Reviewer:

The discussion of results are straightforward without in-depth understanding of the literature and its contribution to filling research gaps.

Author:

Thank you for your suggestion. The discussion has been modified.

 

Reviewer:

Why study agriculture emission is important to China (and maybe the world) has not been well explained.

Author:

Thank you for your suggestion. The Introduction has been modified.

 

Reviewer 4 Report

It is a case study of China and would not be useful for other countries. Authors should consider comparative study with other countries and improve methodologies for analyses. 

Author Response

Reviewer:

It is a case study of China and would not be useful for other countries. Authors should consider comparative study with other countries and improve methodologies for analyses. 

Author:

Thank you for your suggestion. We have already conducted the comparative studies, and have improved methodologies for the analysis of other countries. The manuscript might be completed recently, and we are looking forward to your comments.

Reviewer 5 Report

The article has been improved. Some comments have been taken into account.

However, the main reservations remain unchanged.

The lack of connection between policy recommendations and research results.

 

The issue of measuring the intensity of emissions based on the ratio of emissions to the value of agricultural production. In the presented results, the authors show a decrease in emission intensity from over 0.8 to about 0.25. The reviewer believes that this is mainly due to the change in prices of agricultural products. According to FAOSTAT, in 2000 - 2016 the volume of rice and wheat production in China increased by 12% and 34%, respectively, while the value of all agricultural production [in int. $] by 63%. At the same time, according to the authors, GHG emissions from agriculture increased by 26.7%. This means a reduction of the GHG / Prod. Value by 22.4% in 2016 compared to 2000. While a comparison of physical changes in the volume of wheat and rice production gives a result similar to changes in the level of emissions. So actually no changes in the ratio of emissions and production. For such changes to occur it would be necessary to clearly change the technology and / or change the structure of production.

If constant prices from 2000 were obtained by taking into account general inflation, then the results of the analysis of the intensity of emissions made by the authors are only a comparison of changes in the relation of agricultural production prices to changes in prices in the entire economy.

 

And finally, one note about the writing style:

The 2017 line states: "In 2002, scholars in American proposed ..." who are these scholars, why they proposed in ‘American’ and why exactly scholars and not scientists or researchers?

Actually, the whole next page is written in this style. There are no citation sources in paragraphs 217 to 286.

Author Response

Reviewer:

The article has been improved. Some comments have been taken into account.

However, the main reservations remain unchanged.

The lack of connection between policy recommendations and research results.

Author:

Thank you for pointing it out. Both the policy recommendations and research results have been put forward on the basis of total carbon emission and the intensity of carbon emission, that is, the policy recommendations have been put forward according to the research results.

 

Reviewer:

The issue of measuring the intensity of emissions based on the ratio of emissions to the value of agricultural production. In the presented results, the authors show a decrease in emission intensity from over 0.8 to about 0.25. The reviewer believes that this is mainly due to the change in prices of agricultural products. According to FAOSTAT, in 2000 - 2016 the volume of rice and wheat production in China increased by 12% and 34%, respectively, while the value of all agricultural production [in int. $] by 63%. At the same time, according to the authors, GHG emissions from agriculture increased by 26.7%. This means a reduction of the GHG / Prod. Value by 22.4% in 2016 compared to 2000. While a comparison of physical changes in the volume of wheat and rice production gives a result similar to changes in the level of emissions. So actually no changes in the ratio of emissions and production. For such changes to occur it would be necessary to clearly change the technology and / or change the structure of production.

Author:

Thank you for your question. The agricultural carbon emission in this paper has been measured according to the amount of agricultural products. Taking the carbon emission of different fertilizers as example, the total carbon emission has been calculated according to the amount rather than the prices of fertilizers. What’s more, since the main the influencing factors have been identified by the existing researches and this paper has mainly focused on the study of regional differences and cooperative emission reduction strategies, the decomposition of influencing factors has not been explained in detail.

 

 

 

Reviewer:

If constant prices from 2000 were obtained by taking into account general inflation, then the results of the analysis of the intensity of emissions made by the authors are only a comparison of changes in the relation of agricultural production prices to changes in prices in the entire economy.

Author:

Thank you for your suggestion. The agricultural carbon emission has been measured according to the amount of agricultural production, rather than the agricultural production prices.

 

Reviewer:

And finally, one note about the writing style:

The 2017 line states: "In 2002, scholars in American proposed ..." who are these scholars, why they proposed in ‘American’ and why exactly scholars and not scientists or researchers?

Author:

Thank you for pointing it out. This mislead information is not clear, we rearranged this sentence to make it clear. In our literature part, we review how previous studies do literature review, regarding to using scholars,  not scientists or researchers, this maybe the prefer style of different author. 

 

Reviewer:

Actually, the whole next page is written in this style. There are no citation sources in paragraphs 217 to 286.

Author:

Thank you for pointing it out. We made the changes accordingly and double check the whole paper

 

Round 3

Reviewer 2 Report

The authors' response to my questions in the last round is not convincing. 

Reviewer 4 Report

Authors should revise the paper on the comments. Authors did not revise the paper on the comments on including comparative study with other countries and improve methodologies for analyses in the paper. 

Reviewer 5 Report

The authors did not convincingly answer to previous comments regarding intensity.

As I wrote in the previous review, the statement:

"It can be seen from Figure 1 that the intensity of carbon emissions declined from 0.86 ton / 10,000 yuan in 2000 to 0.24 ton / 10,000 yuan in 2016"

and

"In 2016, China's total carbon emissions were 272.022 million tons, which is 26.67% more than that in 2000"

would indicate an increase in the value of agricultural production by (0.86 / 0.24 * 1.2667 - 1) * 100% = 354%. While production figures from FAOSTAT indicate an increase in the value of agricultural production by 63%.